package com.smm.fliter;

import com.smm.config.JWTToken;
import com.smm.util.JwtUtils;
import org.apache.shiro.authc.AuthenticationToken;
import org.apache.shiro.authz.UnauthorizedException;
import org.apache.shiro.subject.Subject;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.apache.shiro.web.filter.authz.AuthorizationFilter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.net.URLEncoder;

public class JWTFliter  extends  BasicHttpAuthenticationFilter {
    private final Logger logger = LoggerFactory.getLogger(this.getClass());


    /**
     * 如果带有 token，则对 token 进行检查，否则直接通过
     */
    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) throws UnauthorizedException {
        //判断请求的请求头是否带上 "Token"
        logger.info("判断用户请求头是否带有token");
        logger.info("isLoginAttempt(request, response)===>"+isLoginAttempt(request, response));


        logger.info("mappedValue:==>",mappedValue);
        if (isLoginAttempt(request, response)) {
            //如果存在，则进入 executeLogin 方法执行登入，检查 token 是否正确
            try {
                executeLogin(request, response);
                return true;
            } catch (Exception e) {
                //token 错误
                logger.error("isAccessAllowed",e);
            }
        }
        //如果请求头不存在 Token，则可能是执行登陆操作或者是游客状态访问，无需检查 token，直接返回 true
        return true;
    }

    @Override
    protected boolean onAccessDenied(ServletRequest request, ServletResponse response) throws Exception {
        return super.onAccessDenied(request, response);
    }

    /**
     * 判断用户是否想要登入。
     * 检测header里面是否包含Authorization字段即可
     * 如果有就返回 ture
     * 没有就返回 false
     * @return
     */
    @Override
    protected boolean isLoginAttempt(ServletRequest request, ServletResponse response) {
        HttpServletRequest req = (HttpServletRequest) request;
        String authorization = req.getHeader("Authorization");
        String requestURI = req.getRequestURI();
        logger.info("请求URI:"+requestURI);
        return authorization != null;
    }
    /**
     * 执行登陆操作
     */
    @Override
    protected boolean executeLogin(ServletRequest request, ServletResponse response) throws Exception {
        logger.info("执行登录");
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        String token = httpServletRequest.getHeader("Authorization");
        JWTToken jwtToken = new JWTToken(token);
        // 提交给realm进行登入，如果错误他会抛出异常并被捕获
        getSubject(request, response).login(jwtToken);
        // 如果没有抛出异常则代表登入成功，返回true
        return true;
    }

    @Override
    protected boolean isPermissive(Object mappedValue) {
        return super.isPermissive(mappedValue);
    }

    /**
     * 对跨域提供支持
     */
    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        logger.info("开启跨域");
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
        // 跨域时会首先发送一个option请求，这里我们给option请求直接返回正常状态
        if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }


}
